Yoga practice is useful in changing our predominant modus from the sympathetic nervous nervous system which stimulates action and the fight/flight response to the parasympathetic nervous system which calms, relaxes and rejuvenates us. Yoga can rebalance us towards this calming effect. A major key in the process is the incorporation of gentle slow smooth breathing.
Clearing tension is a major function of yoga practice. To release constant tension that has accumulated over a lifetime, requires a lot of attention. Especially profound is releasing tension from the central, core body. And this core body is also an entry to more subtle levels of awareness. Releasing tension is the secret to increasing awareness and to improving movement and wellness. For the body to relax, the stability must be felt from the feet and legs especially.
The above all contributes to the practice of Ahimsa or non-violence. The practice of ahimsa is a mind of gentleness, kindness, patience and compassion.
Ahimsa is one of the essential ingredients of yoga practice that without ahimsa yoga practice may not really be yoga.